In diameter, it is, in effect, 108-1/2 times as large as the Earth; that is to say, if our planet be represented by a globe 1 meter in diameter, the Sun would figure as a sphere 108-1/2 meters across. This is shown on the accompanying figure (Fig. 28), which is in exact proportion. If our world were set down upon the Sun, with all its magnificence, all its wealth, its mountains, its seas, its monuments, and its inhabitants, it would only be an imperceptible speck. It would occupy less space in the central orb than one grain in a grenade. If the Earth were placed in the center of the Sun, with the Moon still revolving round it at her proper distance of 384,000 kilometers (238,500 miles), only half the solar surface would be covered. In volume the Sun is 1,280,000 times vaster than our abode, and 324,000 times heavier in mass. That the giant only appears to us as a small though very brilliant disk, is solely on account of its distance. Its apparent dimensions by no means reveal its majestic proportions to us. When observed with astronomical instruments, or photographed, we discover that its surface is not smooth, as might be supposed, but granulated, presenting a number of luminous points dispersed over a more somber background. These granulations are somewhat like the pores of a fruit, _e.g._, a fine orange, the color of which recalls the hue of the Sun when it sinks in the evening, and prepares to plunge us into darkness. At times these pores open under the influence of disturbances that arise upon the solar surface, and give birth to a Sun-Spot. For centuries scientists and lay people alike refused to admit the existence of these spots, regarding them as so many blemishes upon the King of the Heavens. Was not the Sun the emblem of inviolable purity? To find any defect in him were to do him grievous injury. Since the orb of day was incorruptible, those who threw doubt on his immaculate splendor were fools and idiots. And so when Scheiner, one of the first who studied the solar spots with the telescope, published the result of his experiments in 1610, no one would believe his statements. Yet, from the observations of Galileo and other astronomers, it became necessary to accept the evidence, and stranger still to recognize that it is by these very spots that we are enabled to study the physical constitution of the Sun. They are generally rounded or oval in shape, and exhibit two distinct parts; first, the central portion, which is black, and is called the _nucleus_, or _umbra_; second, a clearer region, half shaded, which has received the name of _penumbra_. These parts are sharply defined in outline; the penumbra is gray, the nucleus looks black in relation to the dazzling brilliancy of the solar surface; but as a matter of fact it radiates a light 2,000 times superior in intensity to that of the full moon. [Illustration: FIG. 29.--Direct photograph of the Sun.]